Many people asked me to open sources of the URU Key. It's sad, but biometrics part of the project does not allow me to do that.
However, I can not leave these requests unattended. I have started a new project - URU Card (https://hackaday.io/project/173443-uru-card). It's an open-source FIDO2 Authenticator built with ESP32 microcontroller and programmed using Arduino Framework.
Feel free to join the project! Unfortunately, I can not put significant effort into it as I am quite busy with other stuff and this is side projects. Nevertheless, I am pretty sure the community is able to move it forward.
You can help the project sharing this information. Thank you!